path: root/experimental/keyboard-leds-trayicons.c

/*
 * File: keyboard-leds-trayicons.c
 * Location: https://bgstack15.ddns.net/cgit/keyboard-leds-trayicons/
 * Authors: bgstack15, jonhoo
 * Startdate: 2022-09-28-4 13:30
 * SPDX-License-Identifier: GPL-3.0
 * Title: Proof of Concept C utility for polling capslock and numlock
 * Purpose: Demonstrate these can be done in C, with the eventual goal of rewriting keyboard-leds-trayicons entirely in C to avoid the "sleep 0.75" in ps output
 * History:
 * Usage:
 * References:
 *    https://github.com/Cairo-Dock/cairo-dock-plug-ins/blob/master/keyboard-indicator/src/applet-xklavier.c#L124
 *    https://github.com/oco2000/xfce4-kbdleds-plugin/blob/fe753d9d0f8a720a35a32f5f556b8fbead798d20/panel-plugin/xkbleds.c
 *    https://stackoverflow.com/questions/60897833/programmatically-calling-mainint-argc-char-argv-in-c
 *    https://stackoverflow.com/questions/18649547/how-to-find-the-length-of-argv-in-c
 *    https://www.geeksforgeeks.org/fork-system-call/
 *    https://stackoverflow.com/questions/43326857/multiple-fork-in-c-program
 *    https://stackoverflow.com/questions/14173268/fifo-files-and-read-write
 *    https://ftp.gnu.org/old-gnu/Manuals/glibc-2.2.3/html_chapter/libc_15.html
 *    https://qnaplus.com/c-program-to-sleep-in-milliseconds/
 *    https://stackoverflow.com/questions/47107311/sending-signal-from-child-to-parent
 *    https://stackoverflow.com/questions/108183/how-to-prevent-sigpipes-or-handle-them-properly
 *    https://cboard.cprogramming.com/c-programming/150795-signal-sigaction-conversion-printable-thread.html
 *    http://maemo.cloud-7.de/irclogs/freenode/_devuan-dev/_devuan-dev.2022-10-01.log.html
 * Improvements:
 *    Use getopts, -h, -c conffile, -d (debug)
 *    fix all return values at end
 * Dependencies: libx11-dev, libinih-dev, libgtk-3-dev
 * Documentation:
 *    features include:
 *       operate when only one trayicon has exited
 *       exit when both trayicons have exited
 */

#include <ctype.h>
#include <fcntl.h>
#include <glib.h>
#include <gtk/gtk.h>
#include <ini.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <X11/XKBlib.h>
#include <X11/Xlib.h>
#include <signal.h>

int debug = 0;
Display* dpy;
typedef struct {
   const char* caps_on;
   const char* caps_off;
   const char* num_on;
   const char* num_off;
   int sleep_microseconds;
   const char* caps_fifo;
   const char* num_fifo;
} configuration;
char* conffile = "none";
char msg[1000];
int closed_icons = 0;

/* START inclusion of mktrayicon.c, 536 lines */
/*
 * This function is made because it's needed to escape the '\' character
 * The basic code has been taken from the man pages of the strncpy function
 */
char *strncpy_esc(char *dest, const char *src, size_t n) {
  size_t i = 0;
  size_t index = 0;
  while (i < n && src[i] != '\0') {
    if (src[i] == '\\' && src[i + 1] != '\0') {
      dest[index] = src[i + 1];
      index++;
      i += 2;
    } else {
      dest[index] = src[i];
      index++;
      i++;
    }
  }
  for (; index < n; index++) {
    dest[index] = '\0';
  }
  return dest;
}

char *save_word(char *src, int i_del, int last) {
  char *dest = malloc((i_del - last) * sizeof(char));
  strncpy_esc(dest, src + last + 1, i_del - last - 1);
  dest[i_del - last - 1] = '\0';
  return dest;
}

/*
 * Struct that stores the label names on the menu and
 * their corresponding actions when the user selects them
 */
struct item {
  char *name;
  char *action;
} * onmenu;
char *onscrollup = NULL;
char *onscrolldown = NULL;
char *onmiddleclick = NULL;
int menusize = 0; // number of menu entries
GtkWidget *menu = NULL;

GtkStatusIcon *icon;
char *onclick = NULL;

void tray_icon_on_click(GtkStatusIcon *status_icon, gpointer user_data) {
  if (onclick != NULL && fork() == 0) {
    execl("/bin/sh", "sh", "-c", onclick, (char *)NULL);
  }
}

void tray_icon_on_middleclick(GtkStatusIcon *status_icon, GdkEventButton *event,
                       gpointer user_data) {
  if (2 == event->button) {
    if (onmiddleclick == NULL) {
      if(debug)
        printf("middleclick, but no command specified\n");
    } else {
      if(debug)
        printf("middleclick\n");
      if (onmiddleclick != NULL && fork() == 0) {
        execl("/bin/sh", "sh", "-c", onmiddleclick, (char *)NULL);
      }
    }
  }
}

/*
 * Callback function for when an entry is selected from the menu
 * We loop over all entry names to find what action to execute
 */
void click_menu_item(GtkMenuItem *menuitem, gpointer user_data) {
  const char *label = gtk_menu_item_get_label(menuitem);
  for (int i = 0; i < menusize; i++) {
    if (strcmp(label, onmenu[i].name) == 0 && fork() == 0) {
      execl("/bin/sh", "sh", "-c", onmenu[i].action, (char *)NULL);
    }
  }
}

void tray_icon_on_menu(GtkStatusIcon *status_icon, guint button,
                       guint activate_time, gpointer user_data) {
  if(debug)
    printf("Popup menu\n");
  if (menusize) {
    gtk_menu_popup_at_pointer((GtkMenu *)menu, NULL);
  }
}

void tray_icon_on_scroll(GtkStatusIcon *status_icon, GdkEventScroll *event,
                       gpointer user_data) {
  char *i = NULL;
  switch (event->direction) {
    case GDK_SCROLL_UP:
      i = "up";
      if (onscrollup != NULL && fork() == 0)
        execl("/bin/sh", "sh", "-c", onscrollup, (char *)NULL);
      break;
    case GDK_SCROLL_DOWN:
      i = "down";
      if (onscrolldown != NULL && fork() == 0)
        execl("/bin/sh", "sh", "-c", onscrolldown, (char *)NULL);
      break;
  }
  if (i != NULL) {
  if(debug)
    printf("scroll %s\n",i);
  }
}

gboolean set_tooltip(gpointer data) {
  char *p = (char *)data;
  if (*p == '\0') {
  if(debug)
    printf("Removing tooltip\n");
    gtk_status_icon_set_has_tooltip(icon, FALSE);
    return FALSE;
  }

  if(debug)
    printf("Setting tooltip to '%s'\n", p);
  gtk_status_icon_set_tooltip_text(icon, p);
  free(data);
  return FALSE;
}

gboolean set_icon(gpointer data) {
  char *p = (char *)data;
  if(debug)
    printf("Setting icon to '%s'\n", p);
  if (strchr(p, '/')) {
    gtk_status_icon_set_from_file(icon, p);
  } else {
    gtk_status_icon_set_from_icon_name(icon, p);
  }
  free(data);
  return FALSE;
}

gboolean set_visible(gpointer data) {
  gtk_status_icon_set_visible(icon, data == 0 ? FALSE : TRUE);
  return FALSE;
}

gboolean do_quit(gpointer data) {
  gtk_main_quit();
  return FALSE;
}

gpointer watch_fifo(gpointer argv) {
  char *buf = malloc(1024 * sizeof(char));
  char cmd;
  char quote;
  char *param;
  char *tmp = malloc(1024 * sizeof(char));
  char *read;
  size_t len, i;
  char *fifo_path = (char *)argv;
  FILE *fifo;
  struct stat fifo_st;

/* outer is for open */
outer:
  while (1) {
    if (stat(fifo_path, &fifo_st) != 0) {
      perror("FIFO does not exist, exiting\n");
      gdk_threads_add_idle(do_quit, fifo);
      return NULL;
    }

    fifo = fopen(fifo_path, "r");

    if (fifo == NULL) {
      perror("FIFO went away, exiting\n");
      gdk_threads_add_idle(do_quit, fifo);
      return NULL;
    }

    /* inner is for read */
    while (1) {
      read = fgets(buf, 1024 * sizeof(char), fifo);

      if (read == NULL) {
        /* no more data in pipe, reopen and block */
        fclose(fifo);
        goto outer;
      }

      /* trim string */
      while ((*read == '\n' || *read == ' ' || *read == '\t') &&
             *read != '\0') {
        read++;
      }

      if (*read == '\0') {
        /* empty command */
        continue;
      }

      cmd = *read;
      len = strlen(read);
      if (len < 3) {
        param = NULL;
      } else if (*(read + 2) != '\'' && *(read + 2) != '"') {
        // unquoted string
        read += 2;
        len -= 2;
        // trim trailing whitespace
        i = len - 1;
        while (i > 0) {
          if (!isspace(read[i])) {
            len = i + 1;
            read[len] = '\0';
            break;
          }
          i -= 1;
        }
        param = malloc((len + 1) * sizeof(char));
        strncpy(param, read, len + 1);
      } else {
        // quoted string
        quote = *(read + 2);
        read += 3;
        len -= 3;
        *tmp = '\0';
        *(tmp + 1024 - 1) = '\0';
        // keep track of what we have so far
        strncpy(tmp, read, 1023);

        // now keep reading until we have the end quote
        while (1) {
          // check for terminating '
          if (len != 0) {
            // search backwards past whitespace
            i = len - 1;
            while (i > 0) {
              if (!isspace(tmp[i])) {
                break;
              }
              i -= 1;
            }
            if (tmp[i] == quote) {
              // maybe the end!
              // let's make sure it isn't escaped
              if (i >= 2 && tmp[i - 2] == '\\') {
              } else {
                // it's not!
                // we're done.
                // trim off the ' and
                // any whitespace we walked past
                len = i;
                tmp[len] = '\0';
                break;
              }
            }
          }

          if (len == 1023) {
            // we can't read any more
            // but also haven't found the end
            // forcibly terminate the string
            fprintf(stderr, "Quoted string too long (max 1023 chars)\n");
            break;
          }

          // we don't have the end of the string yet
          read = fgets(buf, 1024 * sizeof(char), fifo);
          if (read == NULL) {
            /* no more data in pipe, reopen and block */
            fclose(fifo);
            goto outer;
          }
          // note that we don't trim here, because we're
          // in a quoted string.
          strncpy(tmp + len, read, 1023 - len);
          len += strlen(tmp + len);
        }

        // quoted string is now in param[0:len]
        param = malloc((len + 1) * sizeof(char));
        strncpy(param, tmp, len + 1);
      }

      switch (cmd) {
      case 'q':
        gdk_threads_add_idle(do_quit, param);
        if (param != NULL) {
          free(param);
        }
        break;
      case 't': /* tooltip */
        gdk_threads_add_idle(set_tooltip, param);
        break;
      case 'i': /* icon */
        gdk_threads_add_idle(set_icon, param);
        break;
      case 'h': /* hide */
        gdk_threads_add_idle(set_visible, (void *)0);
        if (param != NULL) {
          free(param);
        }
        break;
      case 's': /* show */
        gdk_threads_add_idle(set_visible, (void *)1);
        if (param != NULL) {
          free(param);
        }
        break;
      case 'c': /* click */
        if (onclick != NULL) {
          free(onclick);
          onclick = NULL;
        }

        if (param != NULL && *param == '\0') {
          if(debug)
            printf("Removing onclick handler\n");
          free(param);
          break;
        }

        onclick = param;
        if(debug)
          printf("Setting onclick handler to '%s'\n", onclick);
        break;
      case 'm': /* menu */
        if (onmenu != NULL) {
          // destroy the previous menu
          for (int i = 0; i < menusize; i++) {
            free(onmenu[i].name);
            free(onmenu[i].action);
            onmenu[i].name = NULL;
            onmenu[i].action = NULL;
          }
          free(onmenu);
          onmenu = NULL;
          gtk_widget_destroy(menu);
          menu = NULL;
        }

        menusize = 0;

        if (!param) {
          break;
        } else if (*param == '\0') {
          if(debug)
            printf("Removing onmenu handler\n");
          free(param);
          break;
        }

        // This block makes sure that the parameter after 'm' is ready to be
        // processed We can't accept 2 straight commas, as it becomes ambiguous
        int straight = 0;
        int bars = 0;
        for (int i = 0; i < len; i++) {
          if (param[i] == ',' && param[i - 1] != '\\') {
            straight++;
            if (straight == 2) {
              break;
            }
          } else if (param[i] == '|' && param[i - 1] != '\\') {
            straight = 0;
            bars++;
          }
        }
        if (straight == 2) {
          printf("Two straight ',' found. Use '\\' to escape\n");
          free(param);
          break;
        }
        // End of block that checks the parameter

        // Create the onmenu array which stores structs with name, action
        // properties
        menusize = bars + 1;
        onmenu = malloc(menusize * sizeof(struct item));
        menu = gtk_menu_new();
        int last = -1;
        int item = 0;
        char lastFound = '|'; // what was the last delimiter processed
        for (int i = 0; i < len; i++) {
          if (param[i] == ',' && param[i - 1] != '\\') {
            onmenu[item].name = save_word(param, i, last);
            last = i;
            lastFound = ',';
          } else if (param[i] == '|' && param[i - 1] != '\\') {
            if (lastFound == ',') { // we have found a ',' so we read an action
              onmenu[item].action = save_word(param, i, last);
            } else { // this is a label-only entry
              onmenu[item].name = save_word(param, i, last);
              onmenu[item].action = malloc(1); // pointer has to be freeable
              *onmenu[item].action = '\0';
            }
            last = i;
            lastFound = '|';
            item++;
          }
        }
        if (item < menusize) { // haven't read all actions because last one
                               // didn't end with a '|'
          if (lastFound == ',') {
            onmenu[item].action = save_word(param, len, last);
          } else {
            onmenu[item].name = save_word(param, len, last);
            onmenu[item].action = malloc(1);
            *onmenu[item].action = '\0';
          }
        }

        // Now create the menu item widgets and attach them on the menu
        for (int i = 0; i < menusize; i++) {
          GtkWidget *w;
          if (0 == strlen(onmenu[i].name) || (!strncmp(onmenu[i].name, "-----", 5))) {
            w = gtk_separator_menu_item_new() ;
          } else {
            w = gtk_menu_item_new_with_label(onmenu[i].name);
            g_signal_connect(G_OBJECT(w), "activate", G_CALLBACK(click_menu_item),
                             NULL);
          }
          gtk_menu_shell_append(GTK_MENU_SHELL(menu), w);
        }
        gtk_widget_show_all(menu);
        free(param);
        break;
      case 'R': /* mouse scroll up */
        if (onscrollup != NULL) {
          free(onscrollup);
        }
        if (!param || (*param == '\0')) {
          if(debug)
            printf("Removing scrollup command\n");
          onscrollup = NULL;
        } else {
          if(debug)
            printf("Setting scrollup command\n");
          onscrollup = malloc(strlen(param));
          strncpy(onscrollup, param, len + 1);
        }
        break;
      case 'r': /* mouse scroll down */
        if (onscrolldown != NULL) {
          free(onscrolldown);
        }
        if (!param || (*param == '\0')) {
          if(debug)
            printf("Removing scrolldown command\n");
          onscrolldown = NULL;
        } else {
          if(debug)
            printf("Setting scrolldown command\n");
          onscrolldown = malloc(strlen(param));
          strncpy(onscrolldown, param, len + 1);
        }
        break;
      case 'S': /* mouse middle click */
        if (onmiddleclick != NULL) {
          free(onmiddleclick);
        }
        if (!param || (*param == '\0')) {
          if(debug)
            printf("Removing middle click command\n");
          onmiddleclick = NULL;
        } else {
          if(debug)
            printf("Setting middleclick command\n");
          onmiddleclick = malloc(strlen(param));
          strncpy(onmiddleclick, param, len + 1);
        }
        break;
      default:
        fprintf(stderr, "Unknown command: '%c'\n", *buf);
        if (param != NULL) {
          free(param);
        }
      }

      gdk_flush();
    }
  }
  return NULL;
}

static GtkStatusIcon *create_tray_icon(char *start_icon) {
  GtkStatusIcon *tray_icon;

  if (strchr(start_icon, '/')) {
    tray_icon = gtk_status_icon_new_from_file(start_icon);
  } else {
    tray_icon = gtk_status_icon_new_from_icon_name(start_icon);
  }
  g_signal_connect(G_OBJECT(tray_icon), "activate",
                   G_CALLBACK(tray_icon_on_click), NULL);
  g_signal_connect(G_OBJECT(tray_icon), "popup-menu",
                   G_CALLBACK(tray_icon_on_menu), NULL);
  g_signal_connect(G_OBJECT(tray_icon), "scroll-event",
                   G_CALLBACK(tray_icon_on_scroll), NULL);
  g_signal_connect(G_OBJECT(tray_icon), "button-release-event",
                   G_CALLBACK(tray_icon_on_middleclick), NULL);
  gtk_status_icon_set_visible(tray_icon, TRUE);

  return tray_icon;
}

int print_usage(char **argv) {
  printf("Usage: %s [-i ICON] [-t TOOLTIP] [-h] [FIFO]\n", *argv);
  printf("Create a system tray icon as specified\n");
  printf("\n");
  printf("  -i ICON\tUse the specified ICON when initializing\n");
  printf("  -t TOOLTIP\tUse the specified TOOLTIP when initializing\n");
  printf("  -h \t\tDisplay this help message\n");
  printf("\n");
  printf("If a FIFO is not provided, mktrayicon will run until killed\n");
  printf("Report bugs at https://github.com/jonhoo/mktrayicon\n");
  return 0;
}

int fmain(int argc, char **argv) {
  char *start_icon = "none";
  char *tooltip = NULL;
  char *pipe = NULL;
  GThread *reader;

  XInitThreads(); /* see http://stackoverflow.com/a/18690540/472927 */
  gtk_init(&argc, &argv);

  if (argc == 1) {
    return print_usage(argv);
  }

  int c;
  while ((c = getopt(argc, argv, "i:t:h")) != -1)
    switch (c) {
    case 'i':
      start_icon = optarg;
      break;
    case 't':
      tooltip = optarg;
      break;
    case 'h':
      return print_usage(argv);
    case '?':
      fprintf(stderr, "Unknown option: %c\n", optopt);
      return 1;
    }

  icon = create_tray_icon(start_icon);

  if (tooltip) {
    gtk_status_icon_set_tooltip_text(icon, tooltip);
  }

  /* optind holds the index of the next argument to be parsed */
  /* getopt moved positional arguments (if there were any) to the end of the
   * argv array, without parsing them */
  /* so if there were only non-positional arguments, all arguments have been
   * parsed and optind will be equal to argc */
  if (optind < argc) {
    pipe = argv[optind];
    reader = g_thread_new("watch_fifo", watch_fifo, pipe);
  }

  gtk_main();
  return 0;
}
/* STOP inclusion of mktrayicon.c */

int get_indicator(Display* dpy, char* indicator) {
	// where indicator is one of ["Num Lock", "Caps Lock"]
	Atom lockIndicator = XInternAtom(dpy, indicator, False);
	int st;
	XkbGetNamedIndicator(dpy, lockIndicator, NULL, &st, NULL, NULL);
	return st;
}

// slightly modified from example https://github.com/benhoyt/inih
static int handler(void* user, const char* section, const char* name, const char* value) {
   // KLT does not need section information at all.
   configuration *pconfig = (configuration*)user;
   #define MATCH(n, m, func) if (strcmp(name, n) == 0) { pconfig->m = func(value); }
   MATCH("KLT_CAPS_ON_ICON", caps_on, strdup)
   else MATCH("KLT_CAPS_OFF_ICON", caps_off, strdup)
   else MATCH("KLT_NUM_ON_ICON", num_on, strdup)
   else MATCH("KLT_NUM_OFF_ICON", num_off, strdup)
   else MATCH("KLT_SLEEP_MICROSECONDS", sleep_microseconds, atoi)
   else MATCH("KLT_CAPS_FIFO", caps_fifo, strdup)
   else MATCH("KLT_NUM_FIFO", num_fifo, strdup)
   else {
      return 0; /* unknown section/name, error */
   }
   return 1;
}

void *send_fifo_message(FILE *stream, const char *message) {
   if(debug)
      printf("Msg: %s", message);
   int response = fprintf(stream, message);
   if(debug)
      printf("response: %d\n", response);
   fflush(stream);
}

void *send_fifo_icon_message(FILE *stream, const char *iconfile) {
   // msg is global buffer for messages to dump into a pipe
   strcpy(msg, "i ");
   strcat(msg, iconfile);
   strcat(msg, "\n"); // very important for mktrayicon
   send_fifo_message(stream, msg);
}

void sig_usr(int signo) {
   if(signo == SIGUSR1) {
      printf("an icon has exited!\n");
      closed_icons++;
   };
   return;
}

int fprint_usage(char **argv) {
  printf("Usage: %s [-c CONFFILE] [-d] [-h]\n", *argv);
  printf("Create a system tray icon as specified\n");
  printf("\n");
  printf("  -c CONFFILE\tUse the specified config file (required)\n");
  printf("  -d \tTurn debug messages on\n");
  printf("  -h \tDisplay this help message\n");
  printf("\n");
  return 0;
}

int main(int argc, char **argv) {
   // Step 1: parse parameters
   int c;
   while ((c = getopt(argc, argv, "c:dh")) != -1)
      switch (c) {
      case 'c':
         conffile = optarg;
         break;
      case 'd':
         debug = 1;
         break;
      case 'h':
         return fprint_usage(argv);
         break;
      case '?':
         fprintf(stderr, "Unknown option: %c\n", optopt);
         return 1;
   };
   // must reset this for the inner getopt/optint operations to proceed. This is somehow a globally-scoped variable.
   optind = 0;

   // Step 2: load config
   configuration config;
   if (ini_parse(conffile, handler, &config) < 0) {
      printf("Error: cannot load %s\n",conffile);
      return 1;
   }
   if(debug) {
      printf("Config loaded from %s.\n", conffile);
      printf("caps_on=%s\n", config.caps_on);
      printf("caps_off=%s\n", config.caps_off);
      printf("num_on=%s\n", config.num_on);
      printf("num_off=%s\n", config.num_off);
      printf("sleep_us=%d\n", config.sleep_microseconds);
      printf("caps_fifo=%s\n", config.caps_fifo);
      printf("num_fifo=%s\n", config.num_fifo);
   }

   // Step 3: validate config
   // hardcoded min/max for microseconds, 0 and 10 seconds
   if (config.sleep_microseconds < 0 || config.sleep_microseconds >= 10000000) {
      printf("Warning: invalid sleep_microseconds: %d\n", config.sleep_microseconds);
   };

   // Step 4: initialize variables
   FILE *stream_N, *stream_C;
	dpy = XOpenDisplay( NULL );
	int status_capslock = get_indicator(dpy, "Caps Lock");
	int status_numlock = get_indicator(dpy, "Num Lock");
   char *_argv_C[] = { "fmain", (char*)config.caps_fifo, NULL };
   char *_argv_N[] = { "fmain", (char*)config.num_fifo, NULL };
   int count_C = 0;
   int count_N = 0;
   while (_argv_C[++count_C]);
   while (_argv_N[++count_N]);
   int fd_C, fd_N;
   struct stat st_C, st_N;
   pid_t pid, pid_C, pid_N;
   printf("Capslock: %d\tNumlock: %d\n",status_capslock,status_numlock);

   // Step 5: initiate fifo files
   if (stat(config.caps_fifo, &st_C) != 0)
      mkfifo(config.caps_fifo, 0666);
   if (stat(config.num_fifo, &st_N) != 0)
      mkfifo(config.num_fifo, 0666);

   // Step 6: start child proceses (tray icons)
   // parent 1
   pid = getpid();
   if ((pid_C = fork()) == 0) {
      // parent1->child 1
      fmain(count_C,_argv_C);
      kill(pid, SIGUSR1);
      _exit(0);
   }
   else {
      // parent 1
      if ((pid_N = fork()) == 0) {
         // parent1->child2
         fmain(count_N,_argv_N);
         kill(pid, SIGUSR1);
         _exit(0);
      }
      else {
         // parent 1
         /* prevents breakage when C or N tray icon is closed.
            However, now this daemon will never quit without the closed_icon counter!
         */
         fd_C = open(config.caps_fifo, O_RDWR);
         stream_C = fdopen(fd_C,"w");
         fd_N = open(config.num_fifo, O_RDWR);
         stream_N = fdopen(fd_N,"w");
         strcpy(msg, "m quit,echo 'q' > ");
         strcat(msg, config.caps_fifo);
         strcat(msg, "\n");
         send_fifo_message(stream_C, msg);
         strcpy(msg, "m say hello,yad 'hello'|quit,echo 'q' > ");
         strcat(msg, config.num_fifo);
         strcat(msg, "\n");
         send_fifo_message(stream_N, msg);
         // still parent 1
         // Step 7: loop monitoring logic
         int status_caps_old = -1;
         int status_num_old = -1;
         int kill_result = -1;
         while (closed_icons < 2) {
            //    (1000000); 1 second
            //    (   1000); 1 millisecond
            //    ( 100000); 0.1 seconds is a good number
            usleep(config.sleep_microseconds);
            status_capslock = get_indicator(dpy, "Caps Lock");
            status_numlock  = get_indicator(dpy, "Num Lock");
            //printf("Capslock: %d\tNumlock: %d\n",status_capslock,status_numlock);
            struct sigaction san;
            memset(&san,0,sizeof(san));
            san.sa_handler = sig_usr;
            sigaction(SIGUSR1,&san,NULL);
            if(status_capslock != status_caps_old) {
               kill_result = kill(pid_C, 0);
               // unfortunately, kill does not operate as expected. I expected kill_result <> 0 if the pid is already gone.
               //printf("Checking for capslock change, pid %d, result %d\n", pid_C, kill_result);
               if(0 == status_capslock) {
                  send_fifo_icon_message(stream_C, config.caps_off);
                  printf("capslock off\n");
               }
               else {
                  send_fifo_icon_message(stream_C, config.caps_on);
                  printf("capslock on\n");
               };
               status_caps_old = status_capslock;
            };
            if(status_numlock != status_num_old) {
               if(0 == status_numlock) {
                  send_fifo_icon_message(stream_N, config.num_off);
                  printf("numlock off\n");
               }
               else {
                  send_fifo_icon_message(stream_N, config.num_on);
                  printf("numlock on\n");
               };
               status_num_old = status_numlock;
            };
         }; // end while(1)
         // Either CTRL+C was run twice, or both icons closed
         return 0;
      }; // end parent 1 loop
      return 0;
   }; // end parent 1 loop
   return 0;
}